Always wary of poking an eye out on the sharp end of canes I've hit on a way to make cane caps that's free and easy. Take a walk in a park and collect all those tennis balls you see dogs carrying about and then abandoning when something else takes their interest. Good hunting grounds are by the car parks and entrance gates or you could skulk around the tennis courts.
Cut a hole in them and pop them on the end of the canes. Very Blue Peterish. Here's one I made earlier!